At the present time it is known to provide a mounting or fastening device for securing a reflector of a headlamp on a casing of the latter, the mounting device being of a kind comprising a bar which is mounted on the headlamp casing and which has a spherical head at one end. This spherical head fits in a non-return recess which is arranged in the rear of the reflector. Such a mounting device is used in particular at each of the mounting points of a three point, or tripod, mounting assembly. Tripod mounting assemblies are well known and are used for assembling a reflector to a headlamp casing, so that both the line of sight and the azimuth of the reflector can be adjusted by longitudinal displacement of two of the three heads. A three point mounting assembly is of course one which defines three mounting points which are disposed respectively at the three apices of a right angled triangle.
One disadvantage of the kind of mounting assembly described above lies in the fact that it is necessary not only to obtain absolute precision in the relative positions of the heads when positioning the heads in surface contact with the recesses, but also to position them all at the same time, in order to ensure their correct engagement in the recesses. When a screw head is not aligned exactly with the corresponding recess, it is not possible to engage it in the recess without there being a danger of the components in which the recess is defined being bent or even broken. In this connection it is very difficult to bring the three screw heads into contact in the three corresponding non-return recesses arranged on a triangle, all at the same time. Thus it often happens that two of the screw heads out of three are engaged at the same time while the third head has to be engaged by bending, thus running the risk mentioned above.